/**
 * Copyright 2016 SmartBear Software
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not use this file except
 * in compliance with the License. You may obtain a copy of the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software distributed under the License
 * is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express
 * or implied. See the License for the specific language governing permissions and limitations under
 * the License.
 */

package io.swagger.generator.util;

import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

/**
 * This utility compresses a list of files to standard ZIP format file. It is able to compresses all
 * sub files and sub directories, recursively.
 * 
 * @author Ha Minh Nam
 *
 */
public class ZipUtil {
    /**
     * A constants for buffer size used to read/write data.
     */
    private static final int BUFFER_SIZE = 4096;

    /**
     * Compresses a collection of files to a destination zip file.
     * 
     * @param listFiles A collection of files and directories
     * @param destZipFile The path of the destination zip file
     * @throws FileNotFoundException if file not found
     * @throws IOException if IO exception occurs
     */
    public void compressFiles(List<File> listFiles, String destZipFile)
            throws FileNotFoundException, IOException {

        ZipOutputStream zos = new ZipOutputStream(new FileOutputStream(destZipFile));

        for (File file : listFiles) {
            if (file.isDirectory()) {
                addFolderToZip(file, file.getName(), zos);
            } else {
                addFileToZip(file, zos);
            }
        }

        zos.flush();
        zos.close();
    }

    /**
     * Adds a directory to the current zip output stream.
     * 
     * @param folder the directory to be added
     * @param parentFolder the path of parent directory
     * @param zos the current zip output stream
     * @throws FileNotFoundException if file not found
     * @throws IOException if IO exception occurs
     */
    private void addFolderToZip(File folder, String parentFolder, ZipOutputStream zos)
            throws FileNotFoundException, IOException {
        for (File file : folder.listFiles()) {
            if (file.isDirectory()) {
                addFolderToZip(file, parentFolder + "/" + file.getName(), zos);
                continue;
            }

            zos.putNextEntry(new ZipEntry(parentFolder + "/" + file.getName()));

            BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));

            long bytesRead = 0;
            byte[] bytesIn = new byte[BUFFER_SIZE];
            int read = 0;

            while ((read = bis.read(bytesIn)) != -1) {
                zos.write(bytesIn, 0, read);
                bytesRead += read;
            }

            zos.closeEntry();

        }
    }

    /**
     * Adds a file to the current zip output stream.
     * 
     * @param file the file to be added
     * @param zos the current zip output stream
     * @throws FileNotFoundException if file not found
     * @throws IOException if IO exception occurs
     */
    private static void addFileToZip(File file, ZipOutputStream zos) throws FileNotFoundException,
            IOException {
        zos.putNextEntry(new ZipEntry(file.getName()));

        BufferedInputStream bis = new BufferedInputStream(new FileInputStream(file));

        byte[] bytesIn = new byte[BUFFER_SIZE];
        int read = 0;

        while ((read = bis.read(bytesIn)) != -1) {
            zos.write(bytesIn, 0, read);
        }

        zos.closeEntry();
    }
}
